Far be it for an American to tell the Dutch how to run their business.  :-)  I do get - too easily, perhaps - annoyed when long range planners naively apply Statistics and Probability.  Bit of boring personal history is involved, as well.

The Dutch planners need to junk history and do a re-think.  They need to take a hard look at what is going on as well as consider how to prepare for a relatively rapid, as such things go, sea level rise of 3 meters, conceivably more, over the next 20 years.  Expensive?  Yes.  But less so than having half of the Netherlands under water.  

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre